Study On Vegetation Coverage And Land Desertification Of Qiangtang National Nature Reserve

The vegetation types of Qiangtang Nature Reserve mainly include plateau coldgrassland, hungriness and meadow. Since its foundation, the protection of naturalenvironment and wild animal resources of Qiangtang has got visible improvement.But suffering from the influence of recent economic development and illegal hunt, thefurther planning and development of Qiangtang Nature Reserve is confronted withnew challenge. To cope with new ecological pressure and environmental influence, itneeds new safeguard, and enhances resource management system establishment byintroducing high technology. Study on its vegetation coverage and desertification hasgreat significance in the natural resource sustainable development and protection ofwhole Tibetan Plateau and even the whole country.By the spatial information technology and methods of3S (RS, GPS and GIS),combining with field survey, this study analyzed the reserve’s vegetation coveragechanging trend and made regional evaluation on vegetation degradation, from itsvegetation coverage distribution status, changing trend of the whole area andfunctional area, vegetation coverage changing trend of different land use types.Besides, based on calculation of five desertification testing indexes, the thesisanalyzed the reserve’s desertification dynamic change, and finally made classificationand evaluation. The results are as follows:(1) Classification of the reserve’s vegetation coverage change. The vegetationcoverage change degree was divided into five classes, including clear degraded(<-0.006), light degraded(-0.006--0.002), steady(-0.002-0.002), light improved (0.002-0.006) and clear improved(>0.006).(2) Changing trend analysis and evaluation of the reserve’s vegetation coverage.Based on NDVI-Mean distribution and vegetation coverage change of different land use types, this thesis analyzed the reserve’s vegetation coverage change of thewhole area, each functional area and various land use types, and made regionalevaluation on its vegetation degradation.(3) Land desertification testing index choosing of the reserve. Based oncomparing five desertification testing methods of NDVI, TVDI, MSAVI, LST andAlbedo, it considered that Albedo couldn’t reflect its desertification change. However,the other four indexes had their own advantages which could supplement each otherwhen used comprehensively, and the testing of NDVI was the most integrate andexact.(4) Analysis of the reserve’s land desertification change. Based on testing of fivedesertification indexes analyzed its land desertification dynamic change from2000to2010by different methods. It got that its non-desertification area,middle-desertification area, extremely-heavy-desertification area had decreasing trend,light-desertification area, heavy-desertification area had increasing trend, andnon-desertification area, extremely-heavy-desertification area decreasedcomparatively distinctly while heavy-desertification area increased relativelydistinctly.(5) Classification assessment on land degradation of the reserve. Based on thestudy of (3) and (4), this thesis divided its desertification region into five classes bycomprehensively analyzing environmental elements like land use/coverage type,precipitation, temperature and influencing from human activity in each region of thereserve. It got that its non-desertification area, middle-desertification area,extremely-heavy-desertification area had decreasing trend and area fluctuate relativelyclearly, light-desertification area, heavy-desertification area had increasing trend andarea increased comparatively distinctly. Therefore, these can provide basic data for thedesertification prevention of the reserve.